Some Implications of the Diet of Children in American Samoa

Transcription

1 Call. Antropol. 18 (1994) 1: 7-15 UDC (992.32) Original scientific paper Some Implications of the Diet of Children in American Samoa J. R. Bindon ABSTRACT Both adults and children in American Samoa have been shown to have high rates of obesity and overweight. The nutritional implications of dietary change associated with modernization have been previously described for Adults in American Samoa. The purpose of this paper is to describe and interpret the nutrient intake of American Samoan children. The sample for this study consists of 62 children five to seven years of age. Anthropometric measurements and a 24-hourdietary recall interview provide information about the nutritional status of the children. The Samoan children are large for age, being slightly taller than U.S. children, and substantially heavier. In addition, upper arm muscle circumferences are at or above U.S. medians, while skinfolds are near median values for boys, and above medians for girls. By comparison to RDAs, U.S. Black and White samples, and rural and urban Russian boys, the caloric intakes of the Samoan children are low, as are reported intakes of calcium, phosphorus, iron, thiamine, and riboflavin. With the potential exception of iron deficiency, the low reported intakes of most of these nutrients are discounted because of the absence of clinical symptoms of undernutrition. Instead, obesity and overnutrition are the principal dietary problems requir~ng intervention among the Samoan children. " Introduction The process of modernization, defined here as a change from subsistence-production lifestyles to wage labor and food purchasing, impacts diet at a number of levels. As part of the Samoan Studies Project!, the pattern of modernization of the diet has been characterized in detail for Samoan adults 2-5 These studies show that the Samoan diet is in transition from one based on subsistence farming and fishing to one based on imported foods purchased at markets from earned wages: The research also documents how introduced food items tend to be incorpo- Received for publication December 12,

2 J. R. Bindon:The Diet of SamoanChildren,ColI.Antropol.18(1994) 1: 7-15 rated within Samoan foodways alongside traditional foods 3 As the Samoan diet has changed, Samoan adults and children have become increasingly obese 6,7-1o. The increase in obesity is not necessarily a result of the diet change, but it is no doubt involved in the same process, which also alters patterns of activity9. It is the purpose of this paper to describe reported nutrient intakes and their implications among five to seven year-old children in American Samoa and to provide comparative material to assist in interpretation of the results. Methods and. techniques Sampling: The children in this sample were chosen from among 1,186 children born between January 1974 and September 1976 (95% of all births), who were represented in the Well Baby Clinic records of the Lyndon Baines Johnson Tropical Medical Center, American Samoa. A stratified random sample was drawn based on infant source of milk (breast exclusively until six months, n=30; bottle introduced before six months of age, n=32), infant weight-for-iength status (below the NCHS 25th percentile, n=24; above the NCHS 75th percentile, n=38), and sex (boys, n=31; girls, n=31). A total of 62 children from different households participated in the diet survey, which was conducted during the summer of These children represent approximately 5% of their age/sex group in American Samoa, according to the 1980 Census. The low weight-for-age group was oversampled relative to the population as a whole ll,12,13, hence any biases in this analysis would be in the direction of undernutrition and the social and health concomitants associated with it. The survey was conducted in 32 different villages on the island of Tutuila, American Samoa. Measurements: Anthropometric measurements, including height, weight, up- per arm circumference, triceps and subscapular skinfold were taken on the children. As with all anthropometric surveys done as part of the Samoan Studies Project, the techniques of measurement were those defined by Weiner and Lourie 14. Height was measured with a GPM. anthropometer, weight with a portable balance beam scale, upper arm circumference was measured with a steel tape, and the skinfolds were measured with Lange calipers. Height and weight were measured barefoot, with the children wearing light, tropical clothing. Diet Survey: A 24-hour dietary recall interview was conducted with the child and household food preparer (usually the mother). Both the child and caretaker responded to the questioning. Information about both type and amount of food consumed by the child during the previous 24 hours was gathered. A previous paper considers the frequency of use of food items based on these interviews 15. This paper reports on the nutritional composition of the diet. Nutrient intakes were calcuiated using a FORTRAN program with nutrient composition of common foods coming from the USDA Agriculture Handbook No In addition, estimates of the composition of several tropical foods were obtained from specialized food tables 17,18. SocioeconomicData: A detailed socioeconomic interview was administered by the author to the mother/caregiver for the child. Questions about the household size and structure, income and expenses, including an estimate of the food costs, parents occupation and education, and family gardening activities were asked. The interview was conducted in English unless the caregiver expressed a preference for Samoan. A Public Health Nurse was present to assist with translation when necessary.. Differences in means between boys and girls, breast-fed versus bottle-fed, 8

3 J. R. Bindon:The Diet of Samoan Children,Coll.Antropol.18 (1994) 1: 7-15 TABLE 1 HOUSEHOLD CHARACTERISTICS OF THE SAMPLE - Median Family Size MedianYearsof School,Father MedianYearsof School,Mother MedianAnnual Income MedianMonthlyRent MedianMonthlyFoodBill Father's Occupation: Unemployed/Farmer UnskilledLabor SkilledLabor Professional Mother's Occupation: Unemployed/Housewife UnskilledLabor SkilledLabor Professional Plantation/GardenMaintained: Yes No $6,400 $65 $325 12% 26% 34% 29% 52% 22% 13% 13% 68% 32% and low versus high weight-for-iength groups have all been tested using two sample T-tests, and using the appropriate test statistic for pooled or separate variance depending on the F-test of variance for the groups. Minimum statistical significance has been established as a probability of a Type I error (alpha or p level) of All descriptive and analytic statistics were calculated using SPSS 19. Results The household characteristics of the families participating in this survey are presented in Table 1. The number offamily members ranged from 3 to 22, with a median of 8. A high school education is the norm for both mothers and fathers of the study children. Median annual income was over $6000 (all monetary figures are in U.S. dollars), with a monthly food bill of over $325, as estimated by the principal food buyer for the household. Food prices in the markets are of Samo-a are not cheap, but most families procure food from their gardens and from the sea, reducing the amount of cash that is necessary to purchase food. The monthly rent or house payment estimate of $65 should be interpreted in the context of property ownership in Samoa. Alm9st all land is held jointly by families, and there is very little rental going on. A few families were making payments to builders or renting housing, which accounts for this low figure. Nearly 90% of the fathers were employed, mostly in skilled or professional positions such as teachers, accountants, police, government officials. Less than half of the mothers were employed, mostly in unskilled jobs such as production line workers in the tuna canneries or school cooks. About two-thirds of the households keep family gardens where banana, coconut, taro, and other crops are grown. Many of these gardens are quite small today. The sociodemographic profile of the households that were sampled is consistent with the population as described in 9

4 J. R. Bindon: The Diet of Samoan Children, Coli. Antropol. 18 (1994) 1: 7-15 TABLE 2 AGE AND ANTHROPOMETRIC CHARACTERISTICS OF CHILDREN IN AMERICAN SAMOA PARTICIPATING IN THIS SURVEY Characteristic Age, years Height, cm Weight, kg Body mass index, kg/m 2 Upper arm circumference, cm Arm muscle circumference, cm Triceps skinfold, mm Subscapular skinfold, mm Note: No differences were,significant at p S Boys (N=31) Mean : s.d Girls (N=31) Mean s.d the 1980 census, with the exception ofthe deliberate omission of childless households in the research design. For the three dimensions of the sampling design, infant feeding, infant weight-for-iength status, and sex, there were only two statistically significant differences in anthropometric measurements or nutrient intakes. The children who had been bottle-fed before six months were slightly heavier at age six than the children who had been breastfed, and the children who had been above the 75th percentile of weight-for-iength as infants were slightly taller than those who had been below the 25th percentile. There were no significant differences in age, any of the anthropometric measurements, or any of the nutrient intakes between the boys and girls. Means and standard deviations of age, height, weight, body mass index, upper arm circumference, arm muscle circumference, as well as triceps and subscapular skinfolds for the 62 children are presented in Table 2. The average age is a little more than 6 years 7 months. The mean height is slightly over 120 cm for boys and slightly under for girls. These mean statures are between the 50th and 75th percentile of height for age according to NCHS standards 2o Nearly two-thirds of the Samoan children are taller than the NCHS median for 6-1/2 year-old U.S. children. The weight of the Samoan children averaged between 24 and 25 kg. These mean values are between the 75th and 90th NCHS percentiles 23 Over half of the Samoan children have weights that exceed the NCHS 75th percentile. Body mass index was 17 for the girls, and just slightly less for the boys. These average values fall above the 75th percentile of U.S. white children 21. The high average body mass index of the Samoan children indicates that not only are the Samoans heavy, they are also heavy when their somewhat taller statures are taken into account. Upper arm circumferences averaged just over 18 cm for both boys and girls. These values are only slightly above the median for U.S. children 22 The arm muscle circumference was over 15 cm for boys and 14 cm for girls. The muscle circumference for the boys exceeds U.S. medians, with over of the Samoan boys falling in the top 15 percent of the U.S. distribution 25 The average muscle circumference for the Samoan girls is near the U.S. median, and the distribution of values is, very similar for both U.S. and Samoan girls. Triceps skinfolds averaged 9 mm for boys and over 11 mm for girls. The boys average is comparable to U.S. white chil- 10

5 J. R. Bindon:The Diet of Samoan Children, ColI.Antropol.18 (1994) 1: 7-15 TABLE 3 REPORTED INTAKES OF SELECTED NUTRIENTS FOR AMERICAN SAMOAN, U. S. WHITE!, U. S. BLACK! AND RUSSIAN 2 CHILDREN AGED 6-7 YEARS ' AmericanSamoa(bothsexes) U. S.(both sexes) Russian boys White Black Rural Urban Nutrient Mean s.d. Median Mean Mean Mean Mean Energy,kcal 1, ,444 1,977 1,825 2;139 2,040 Protein, gm Fat, gm Carbqhydrate,gm /- Calcium,mg , Phosphorus,mg Iron, mg VitaminA, 1. U. 2,510 3,265 1,200 3,876 4, Thiamine,mg Riboflavin,mg Niacin, mg Vitamin C, mg Abraham et al Steele et al dren, while the girls average skinfold is closer to the 75th percentile of U.S. whites 24 The subscapular skinfolds averaged 9 mm for girls and just unde'r 7 mm for boys. The boys average is at the 75th percentile of U.S. white children 24 From the high values of all of the anthropometric measurements, a picture emerges of the Samoan children as large, with substantial muscle mass, and with even more substantial fat stores. The anthropometric measurements ofthe Samoan children suggest that on average these Samoan children are reasonably tall and they border on obesity. Since there were no differences in reported nutrient intakes for boys and girls or for infant feeding or infant weight-forlength status sampling groups, the sample has been pooled to characterize their nutrient intake. The reported intakes of selected nutrients for the Samoan children are presented in Table 3, along with age-matched comparison values from U.S. Whites and Blacks 23 and a sample of rural and urban boys from Russia 24 All three of these surveys used a single 24- hour recall diet interview to ascertain intake. The Samoan children report higher intakes of Vitamin C than the U.S. White or Black samples or the Russian boys. In addition, the Samoan. children reported higher Vitamin Aintake than the Russian boys. For energy, protein, calcium, iron, thiamine, riboflavin, a'nd niacin, the Samoan children reported lower intakes - than either the U.S. or Russian samples. The mean caloric intake for the Samoan children was 1,579 kcal, which is in the lower part of the range of recommended intakes for 4-6 year olds 25 Both the U.S. and the Russian children report exceeding the RDA for energy. The mean protein intake of the Samoans of 44 gm is more than adequate for this age group, as is the case for the U. S. and Russian samples also. About two-thirds of the Samoan children reported protein intakes at or above the RDA level, suggesting that there is little if any problem with obtaining adequate protein intakes. 11

6 J. R. Bindon:The Diet of Samoan Children,ColI.Antropol.18 (1994) 1: 7-15 TABLE 4 REPORTED INTAKES 'OF SELECTED NUTRIENTS FOR AMERICAN SAMOAN, U. s. WHITE\ U. S. BLACK! AND RUSSIAN 2 CHILDREN AGED 6-7 YEARS AS A PERCENT OF THE U. S. RDA Mean % RDA American U.S. U. S. Russian Russian Nutrient Samoa White Black Rural Urban Energy Protein Calcium Iron VitaminA Thiamine Riboflavin Niacin Vitamin C Abraham et aj Steele et aj Both calcium and phosphorus intakes appear to be quite low for the Samoan children, about half the RDA values. Eighty percent of the children have calcium intakes below the RDA, and half of the children have intakes of 50% or less of the RDA. The Russian boys also report low calcium intakes. The Samoan children report iron intakes of about twothirds of the RDA, with about 1/4 of the sample reporting intakes ofless than 50% of the iron RDA. Children from the U.S. Black sample also report slightly lower than desired intakes of iron. Intakes of vitamins A and C appear to be more than adequate for all of the groups of children. However, reported intakes of thiamine, riboflavin, and niacin are substantially lower than recommended levels for the Samoan children. Discussion There are several limitations of this, study which need to be considered before discussing nutritional status. First, there are problems with using a 24-hour recall survey. While a single interview does not provide a good estimate of individual in- take, it provides a reasonable estimate of group intake, which is how it has been used in this survey. Working with children and their recall can create additional errors; however, some of that problem has been addressed in this research by including the food preparer in the diet interviews. A more serious source of error is food consumed away from home by the children of which they do not want their caregiver to be aware. Child-following would produce a more complete description of the diet ofthe children, but it was not feasible within the scope of the survey. While the sample was originally drawn to reflect specific aspects of infancy of the children, the household profiles are well representative of American Samoa. American Samoa has undergone the epidemiological transition, and most causes of death are related to modern life styles, including cardiovascular diseases, diabetes, and cancer In view of the significance of heart disease and diabetes, a favorable aspect of the diet of the children in this survey is that only about of the calories come from fat, with over 60% of the calories coming from carbohy- 12

7 J. R. Bindori.: The Diet of Samoan Children, CoIl. Antropol. 18 (1994) 1: 7-15 drates. Unfortunately, much of that carbohydrate load is in the form of processed carbohydrates, especially from the use of sugar in sweets and sodas. The very low reported caloric intakes make it likely that the data suffer from under-reporting. Since the Samoan children are both taller and heavier than the RDA recommended heights and weights, the fact that their caloric intakes are low could be a source of concern. However, it should be pointed out that the Samoan children are not an extremely active group. In our survey, the favorite activity of most ofthe children was watching television. Thus, their energy requirements may be lower than predicted by the RDA, and the deficit may not be as large as.indicated in Tables 3 and 4. The same cannot be said for all of the nutrient deficiencies suggested by this survey, and further exploration is certainly warranted. There are no clinical symptoms to suggest that chronic malnutrition with regard to calcium is occurring. Skeletal growth in the Samoan children proceeds at an adequate rate, and the robusticity of their skeleton is considerable 7,8. Bread- 'fruit and milk are two calcium-rich foods which are frequently consumed by the Samoan children. Both, however, have drawbacks. Breadfruit is a seasonal crop, providing a plenteous source of calcium three times a year. Milk is an expensive import to Samoa, although it is becoming a more common consumable in the Samoan dietary. There are also two types of traditional foods that could contribute substantial calcium to the diet, and which are both likely to be under- or unreported. These foods are coconut water which would be consumed when the child is off in the»bush«and shellfish eaten raw while playing on the reef. Thus, the children may be getting substantially more calcium in their diet than is indicated by the survey. By contrast, there is corroborative evidence suggesting that the iron intake might be lower than it should be and could be leading to a clinically significant problem. School children in American Samoa have low hematocrits 29 and a clinically significant iron deficiency has been reported for pregnant women in neighboring Western Samoa 30. Bananas and papaya are leading,traditional food sources of iron in Samoa. The consumption ofbanarias and papaya may be responsible for the relatively high intakes of Vitamins A and C by comparison to the other nutrients. However, the concentration of iron in these fruits cannot supply sufficient iron to meet the needs of the children. The Samoan children report alarmingly low intakes of thiamine, riboflavin, and niacin. However, these low reported intakes of the B-complex vitamins for the Samoan children do not appear to have any clinical concomitant or other corroborating data. Some of these vitamins may be getting into the children's diet from the same cryptic consumption of shellfish discussed above for calcium intake. In the absence of any clinical findings, I would not view these low reported intakes with great concern. While the reported intakes of the Samoan children in this survey tend to be low relative either to the RDAs or to the comparison children from the U.S. and Russia, the Samoan children are as big or bigger in height, weight, and arm circumference than the RDA standards or the children in the U.s. and Russian samples. In spite of the low reported intakes among these American Samoan children, on the basis of their growth status, body composition, and general good health, it would appear that the nutritional quality of their diet is mostly adequate. Given what we know about adult morbidity and mortality, any efforts to shape the diet of these children should focus Onthe avoidance of obesity and its frequent sequelae in this population of diabetes and cardiovascular disease. 13

8 J. R. Bindon: The Diet of Samoan Children, Coil. Antropol. 18 (1994) 1: 7-15 AcknovvledgeDlents. This research was supported in part by the Research Grants Committee, the Capstone International Program, the College of Arts and Sciences, and the Department of Anthropology of the University of Alabama. Dr. Claudina Cabrera-Mereb assisted with both field work and data preparation. Without the cooperation of the families and the Public Health Nurses in American Samoa, this work would not have been possible. REFERENCES 1. BAKER, P.T., J.M. HANNA, T.S. BAKER. The Changing Samoans: Behavior and Health in Transition. (Oxford University Press, New York, 1986) BINDON, J.R. Ecology of Food and Nutrition 12 (1982) BINDON, J.R., Food and Foodways 3 (1988) BINDON, J.R., Ecology of Food and Nutrition 14 (1984) HANNA, J.M., D.L. PELLETIER, V.J. BROWN, The diet and nutrition of contemporary Samoans. In: The Changing Samoans: Behavior and Health in 'Ii'ansition, P.T. Baker, J.M. 'Hanna, and T.S. Baker (eds), (Oxford University Press, New York, 1986) BINDON, J.R., P.T. BAKER, Ann. Hum. BioI. 12 (1985) BIN- DON, J.R., S.M. ZANSKY, Ann. Hum. BioI., 13 (1986) BINDON, J.R., S.M. ZANSKY. Growth and Morphology. In: The Changing Samoans: Behavior and Health in Transition, P.T. Baker, J.M. Hanna, and T.S. Baker (eds), (Oxford University Press, New York, 1986) BINDON, J.R. Polynesian responses to modernization: Overweight and obesity in the South Pacific. In: Social Aspects of Obesity, I. de Garine and N.J. Pollock (eds), (Gordon and Breach, London, In press.) MCGARVEY, S.T., J.R. BIN- DON, D.E. CREWS, D.E. SCHENDEL. Modernization and adiposity: Causes and cons'equences. In: Human Population Biology: A Transdisciplinary Science, MA Little, J.D. Haas (eds). (Oxford University Press, London, 1989) BINDON, J.R., Medical Anthropology, 9 (1985) BIN- DON, J.R., C. CABRERA. Hum. BioI., 60 (1988) BINDON, J.R., C.C. CABRERA-MEREB" Am. J. Hum. BioI., 2 (1990) WEINER, J.S., J.A. LOURIE, Human Biology. (F.A. Davis Co., Philadelphia, 1969) BINDON, J.R. Ecology of Food and Nutrition, 18 (1986) ADAMS, C.F. Nutritive Value of American Foods in Common Units. Agriculture Handbook No (Agricultural Research Service, u.s. Department of Agriculture, Washington, D.C., 1975) PLATT, B.S. Tables of Representative Values of Foods Commonly Used in Tropical Countries. Medical Research Council Special Report Series No (Her Majesty's Stationery Office, London, 1962) WENKHAM, N.S., C.D. MILLER. Composition of Hawaii Fruits. Hawaii Agricultural Experiment Station, Bulletin No (College of Tropical Agriculture, University of Hawaii, Honolulu, 1969) SPSS Incorporated. SPSS-X Users Guide, 3rd edition. (SPSS Inc., Chicago, 1988) HAMILL, P.V.V., TA DRIZD, C.L. JOHNSON, R.B. REED, A.F. ROCHE. NCHS Growth Curves for Children: Birth-18 years. United States Vital and Health Statistics Series 11, No. 165., DHEW Publication No (U.S. Department of Health, Education, and Welfare, Washington, D.C., 1977) CRONK, C.E., A.F. ROCHE, Am. J. Clin. Nut., 35 (1982) FRISANCHO, A.R., Am. J. Clin. Nut., 27 (1974) ABRAHAM, S. M.D. CARROLL, C.M. DRESSER, C.L. JOHNSON, Dietary Intake Findings United States, DHEW Publication No. (HRA) (U.S. Department of Health, Education, and Welfare, Washington, D.C., 1977) STEELE, M.G., J.H. SPURGEON, K.E. FRENCH, w.k. GIESE, V.N. UTENKO, P.V. BUNDZEN, VA ROGOZKlN, Am. J. Hum. BioI. 6 (1994) NATIONAL RESEARCH COUNCIL (U.S.). Subcommittee on the Tenth Edition of the RDAs. Recommended Dietary Allowances; 10th Edition. (National Academy Press, Washington, D.C., 1989) CREWS, D.E., Hum. BioI., 60 (1988) CREWS, D.E., Am. J. Hum. BioI., 1 (1989) BINDON, J.R., D.E. CREWS, W.W. DRESSLER. Coll. Anthropol., 15 (1991) LIVINGSTONE, S. (Personal Communication, 1989) WOOD, C.S., L.P. GANS. Hum. BioI., 53 (1981) 269. J. R. Bindon Department of Anthropology, University of Alabama, Tuscaloosa, AL , USA J 14

9 .J J. R. Bindon:The Diet of Samoan Children, Coll.Antropol. 18 (1994) 1: 7-15 NEKE POSLJEDICE PREHRANE DJECE SA AMERICKE SAMOE SAZETAK Pokazalo se da su povecana tjelesna tezina i pretilost prisutne u grupi kako u odraslih, tako i u djece sa Americke Samoe. Utjecaji promjena u prehrani povezane su sa modernizacijom koja je opisana. u slucaju odraslih populacija sa AmeriCke Samoe. Svrha ovog rada je opisati i interpretirati prehranu.djece sa AmeriCke Samoe. Uzorak za ovo istrazivanje sastoji se od 62 djece od pet do sedam godina. Antropometrijska mjerenja i intervju 24 satnog izvjesca 0 prehrani pruzaju informaciju 0 prehrambenim navikama djece. Samoanska djeca su velika za svoju dob, nesto visa od americke djece i znatno teza. Uz to, opseg misica nadlaktice su isti ill veci od medijana americke djece, dok su kozni nabori priblizni medijanu za djecake, a veci od medijana za djevojcice. U usporedbi (RDKs) sa uzordma bijelaca, cmaca, te ruralnih i urbanih ruskih djecaka, kaloricni, unosi samoanske djece su mali, isto kao i zabiljezeni unosi kalcija, fosfora, zeljeza, tiamina iriboflavina. Sa izuzetkom nedostatka zeljeza, nisko zabiljezeni unosi vecine hranjivih tvari su iskljuceni s obzirom na odsutnost klinickih simptoma neishranjenosti. Nasuprot tome, pretilost i prekomjema ishrana su osnovni principi problema ishrane koji zahtjevaju intervenciju medu samoanskom djecom. 15